The present invention relates to hypodermic needles and particularly a right angle safety needle that is to be used with infusion therapy.
For intravenous therapy where a medicament fluid is directly introduced to the vein of a patient, a needle or some other venous access device is usually used. Conventional needles are generally used for short term treatments, as the contaminated needles are used but once. For long term treatment whereby a fluid may be repeatedly infused to the patient, the prior art teaches the use of implantable devices such as for example a port or portal that has attached thereto a catheter that routes the fluid through the port to a site remote from the implanted port. The implanted port is accessed by a needle being inserted through the patient""s skin into a septum. Fluid may then be introduced through the port so as to be routed by the catheter from the port to the desired remote site. When an implanted port is used, the needle most likely is a right angle needle that needs to be changed periodically. But each time that a needle is removed, there is always the chance that the healthcare worker handling the needle may be pricked by the contaminated needle. An easy to use, yet reliable, right angle safety needle having a protective system is therefore needed for infusing fluids to a patient as for example by means of an implanted port.
One such right angle hypodermic safety needle is disclosed in Rosato et al. U.S. Pat. No. 5,951,522. The ""522 safety needle uses a number of interconnected foldable flaps hung from the horizontal portion of the right angle needle. The fact that the two lowermost flaps need to be pressed together to secure the tip of the contaminated needle therebetween means that the healthcare worker""s fingers could be subjected to the risk of coming into contacted with the contaminated needle. A second embodiment of the right angle safety needle disclosed in the ""522 patent uses the patient""s skin as a fulcrum for withdrawing the needle. The problem with the approach taught by the alternative embodiment is that it subjects the patient to unnecessary discomfort inasmuch as sufficient pressure has to be applied to the area of the patient adjacent to the needle in order to withdraw the needle from the patient.
There is therefore a need for a right angle safety needle that is simply constructed and yet is readily usable without exposing the contaminated needle to the user and at the same time causing too much discomfort to the patient.
The right angle safety needle of the instant invention utilizes a pivoting movement for withdrawing the needle from a patient. In particular, the needle of the instant invention has a base that rests planarly on the skin of a patient when the needle is to be inserted to the patient to, for example, establish a fluid communication path with a port implanted into the patient. The base has a distal end and a proximal end. An opening or aperture is provided at the distal end wherethrough the vertical portion of the right angle needle extends. The horizontal portion of the right angle needle is encased in an arm by for example being molded to a synthetic and non-allergic material such as plastic. The arm in turn is connected to a conduit wherethrough fluid is flowable.
At the proximal end of the base there is an upright, in the form of two upraised members or sidewalls to which the arm is hingedly connected, so that the arm is pivotable about the upright. The position of the right angle, or L-shaped, needle before and during use is such that the horizontal portion of the needle lies in parallel to the length of the base and the vertical portion extends through the aperture at the distal end of the base. The sharp tip of the needle is offset from the vertical needle portion, as is conventionally known. To keep the right angle needle in the aforenoted position, a holding clip is placed over the front end of the arm for securing the arm to grooves formed at a dam or backstop that extends from the distal end of the base.
After insertion, to remove the needle from the patient, the holding clip is first removed from the front end of the arm. Thereafter, the healthcare worker could either place a thumb under a front extension of the arm or simply push or pull the arm upwards so that the aft portion of the arm is pivoted about the upright at the proximal end of the base. As the arm is pivoted upwards, the vertical portion of the needle is withdrawn from the patient. Once the sharp tip of the needle clears the aperture at the distal end of the base, due to it being offset from the longitudinal axis of the vertical portion of the needle and the natural tendency of the vertical portion of the needle to return to its natural shape vis a vis the horizontal portion of the needle, the sharp tip of the needle is biased forward away from the aperture at the base and gets caught in a well or basin adjacent to the aperature. A dam or backstop circumventing the well prevents the tip of needle from any further forward movement, thereby trapping and retaining the tip of the needle in the well.
Stop portions may be provided at both the upright and the arm to ensure that the arm could only be pivoted to a predetermined angle relative to the base. This ensures that the tip of the needle, once trapped in the well, could not be further removed from the well.
To ensure that it is not just the vertical portion of the needle that prevents downward movement of the needle, a second embodiment of the instant invention provides a stop mechanism or part at either the upright or the base to prevent downward movement of the arm, once the arm has been pivoted to the predetermined angle relative to the base. Thus, with stop mechanisms that prevent the needle from further upward and downward movements, once removed from the patient and trapped in the well, the tip of the contaminated needle will remain fixedly retained in the well of the base.
It is therefore an objective of the present invention to provide a safety needle that is both convenient to use and enables a user to avoid any potential contact with the tip of a contaminated needle.
It is yet another objective of the present invention to provide a right angle safety needle system that has a construction that ensures that the tip of a needle, once trapped, will remain fixedly retained within a catch integrated to the system.